A common cause of wasting domestic water is a flush-toilet water inlet-valve that does not close when the water has risen to a desired level and water continues to fill tank until it dumps into overflow pipe. Often this is a quiet, small flow that causes great water loss as it continues for long periods of time undetected. Some of the reasons for this malfunction are decreasing efficacy of seating members of the water inlet-valve and variations in water pressure in which an increase is too strong a force for the shut-off setting of the tank float. A float setting could be correct for a time when many are watering their lawns but if it rains or becomes non-gardening season the water pressure can increase and the original shut-off setting is too weak to close inlet-valve before water rises to overflow level. A common remedy is to bend the float-rod downward to increase the buoyant force of the float at a water level below the overflow level. This hit and miss approximation by bending is immediately effective in lowering the water level at which inlet-valve closes but, eventually, further hit and miss bending and unbending is necessitated as pressures and valve efficiency change. Since a dead-center downward bend is practically impossible there is a tendency for the float, as a resultant force of its upward buoyant force, to revolve around the original axis of the float rod which is threaded into the inlet-valve. Often these threads become loose and the float revolves 180 degrees or, if the bend has been severe, the float will revolve about 45 degrees and scrape along the tank wall. In either event there is much water loss and inconvenience before the condition is corrected.
Another common cause of domestic water waste is a flush tank water level that is higher than necessary to effectively flush the toilet bowl.